You often hear about the need to change water management – and for some this ‘change’ could invoke images of massive structural changes with pipes and dams and concrete infrastructure involved. But I propose that some of the most powerful changes in water management could be how we conceptualize water management.
1. Get rid of the term “end user.” “End user” is a term commonly used by water managers to describe the people and businesses who use water for drinking, washing, industrial operations etc. “End use” implies that delivering water to people is the “end goal.” However, a quick look at a diagram of the urban water cycle (below) clearly shows delivering water to people is not at the end. This stage is right in the middle of a cycle that repeats several times. Now, I’m not just being nit-picky, or demonstrating my mastery at reading a flow chart: the problem with the term is that it’s the wrong way to think about water. It places the emphasis on delivering water to people, and, while that’s clearly very important, urban water management should focus on more than delivering water.
2. Capitalize on the fact that water management is energy management. Energy generation should be co-equal goal in water management. Water has energy whenever it its flowing downward (kinetic and potential energy), whenever it contains heat (thermal energy), and whenever it becomes sewer water (chemical energy). Capturing that energy means that water can play a bigger part in our energy generation mix – not just hydroelectric dams at huge reservoirs, but in the pipes and conduits where water is regularly flowing. For example, when water pressure is too high, often a pressure regulator is used to reduce it. In many cases a small hydro turbine can do the same job as the pressure regulator and generate electricity at the same time. The heat from hot water, such as when your shower water flows down your drain, can actually be captured and put back into your water heater, reducing your energy usage and bill.
Water utilities – and especially wastewater utilities – need to see themselves as players in energy. A handful of wastewater treatment plants in the U.S. are leading the way in this, striving to achieve net-zero energy – meaning they produce as much energy on-site as they generate annually. East Bay Municipal Utility District in California actually produces more energy than they use in a year! They capture the energy in the water with hydro turbines, and they also capture energy from the biosolids (yes that’s what you think it is) extracted from wastewater. Those biosolids – along with used food scraps collected from restaurants – decompose in a controlled environment. This process creates gases that are used to spin a turbine, which then creates electricity. So not only is energy generated, but food scraps (a significant part of municipal solid waste streams) are used beneficially, rather than just decomposing in a landfill.
3. Eliminate the term “wastewater.” This term is even more offensive because “wastewater” contains approximately 10x the amount of energy that is used to treat it to drinking water standards (says WERF). WOW. The energy in the water is part thermal, part kinetic, and part chemical – and enough of it can be captured to partially or entirely offset the energy demands of the wastewater treatment plant. So let’s start calling water at this stage of the cycle “resource water.” Got a better name? Email me. It needs to be something that communicates its value, and that the water at this stage is not something to be wasted.
So what this all boils down to is that water management shouldn’t be just water management – it can be about a cycle that address multiple resources. We’ve already got the technology to do it, what’s needed now is an expanded way of thinking about all the resources that water provides, and the roles that water managers can play. It’s about managing water, energy and resource systems in the water cycle to support a community’s higher quality of life.